3. Posterior-to-Anterior Segmental Hypermobility: The participant will lie on his/her stomach and the examiner will apply a posterior-to-anterior (back-to-front) force over the spinous processes from S1 to T12 (just below the belt-line to the rib cage). The available mobility will be graded hypermobile (too much motion), normal, or hypomobile (too little motion).